An energy-exergy analysis was undertaken in order to optimize the operational conditions of a SOFC-based power plant fueled by ethanol. A certain plant configuration was contemplated, equipped with an external steam reformer, an afterburner, a mixer and two heat exchangers (preheaters). The most significant operational parameters are enunciated and their influence on the energy and exergy balances of the plant is discussed and optimized. An optimization strategy is presented and optimally controlled unit operations are specified through minimization and allocation of exergy costs.